treatment options? failed keytruda (5 injections), and likely ippi and nivo (2 so far)-Acral Lentiginous

Hi,
My mom was diagnosed with acral lentiginous melanoma on her left foot in June 2016, stage 3c. It was Breslow 4, ulcerated. The sentinel lymph node was positive. The wound originally appeared in January 2016, but was not diagnosed until June.
The PET scan that summer looked clean. We elected to do watch and wait on the lymph nodes, recommended by Dr. Coit at MSK.
In end of October 2016, mom detected palpable nodes in the left groin. The CT scan showed positive lymph nodes in left groin, and the lymph node biopsy with ultrasound confirmed melanoma in the node. The technician poked the node 4 times (twice with fine needle, and twice with core needle).
Mom underwent the lymph node dissection surgery 11/22/2016. They removed both superficial and deep lymph nodes from left groin, since the cloquet's node separating superficial and deep showed positive during the surgery. Out of 9 superficial nodes examined, 3 were positive for melanoma; plus the cloquet node; plus 3 were positive out of 12 examined pelvic lymph nodes. Extra-capsular extension was identified in one superficial and in cloquet node.
In January 2017, the CT scan showed a small met in the illiac bone, and she was put on Keytruda.
On March 27, 2017, after 3 Keytruda injections, the PET scan showed few new bone mets as well as small pulmonary nodes:
-Right proximal femoral shaft, SUV 3.9
-Left femoral neck, SUV 5.0
-Right clavicle, SUV 2.9
-Possible focal uptake in T3 vertebral body, SUV 3.2

We decided to give Keytruda more chance to work and had two more injections every 3 weeks.

In May 2017, mom suddenly felt she couldnt step on her left leg, and the PET scan on May 19, 2017 showed increased malignancy in bone, liver, and lungs:
Marked increase in FDG avid osseous metastases:
-Left femoral neck expansile lytic lesion [SUV 12.9, previously 4.9]
associated with cortical disruption
-Right proximal femur [SUV 18.2, previously 3.9]
-New left posterior iliac bone lesions [SUV 7.2 and 8.9]
-New C3 vertebral body[SUV 8.6]
-Right proximal clavicle [SUV 8.2, previously 2.9]
New mild T11 compression fracture (less than 25 %)
Increase in uptake extent of FDG avid right anterior abdominal
wall/intramuscular soft tissue [SUV 4.0]
IMPRESSION: Since March 27, 2017,
Increased malignancy including osseous, pulmonary, hepatic, and abdominal
wall metastases. Left hip metastasis at risk for pathologic fracture.

So mom was called for an emergency left hip replacement surgery, that was done on May 22, 2017.

Subsequently, mom entered an Ippi/Nivo combo plus Radiation clinical trial, recommended by Dr. Wolchok, and had 2 injections of Ippi/Nivo every 3 weeks (on 6/07/2017 and 6/28/2017), as well as 10 radiation sessions to T3 and T12 of her spine every day starting on 6/22/2017.

Before the last radiation treatment on 7/5/17 , she started experiencing persistent nausea and vomiting. Also severe burning in her esophagus, which was burnt as a side effect to the radiation to the spine. She had difficulty swallowing anything because of the esophagitis, as well as vomiting.

On July 6, 2017, she had a PET scan simulation done to evaluate for radiation to the right clavicle bone, and the scan revealed further progression:

"Increased hypermetabolic osseous metastatic disease. For example:
* C2 vertebra, SUV 9.1, previously 4.8
* Right proximalclavicle, SUV 8.2, previously 8.2, increased in extent
* Right proximal humeral diaphysis, SUV 6.8, previously 2.6
* Left posterior iliac bone, SUV 10.5, previously SUV 8.9, now more
extensive left acetabulum, SUV 7.3, new
* Right mid femoraldiaphysis, SUV 3.4, new
Interval left hip arthroplasty with longstem femoral component with
persistent uptake at the femoral neck, correlating with a site of known
metastasis.
Overlap of osseous activity with the spinal cord at multiple levels
including at T3 and T12, correlating with known epidural extension of
disease.
New mild compression fracture at the T12 level with less than 25 percent
vertebral height loss.
Decreased uptake within a right anterior abdominal wall soft
tissue/muscular nodule, SUV 2.2, previously 4.0.
OTHER FINDINGS: None.
IMPRESSION:
1. Since May 19, 2017, increased malignancy including pulmonary, hepatic
and osseous metastatic disease. Increased pulmonary and nodal disease
since CT of June 5, 2017.
2. New left common iliac and left inguinal nodal metastases.
3. Overlap of activity from osseous metastatic disease with the spinal
cord consistent with known epidural disease better assessed on prior MRI
spine.
4. New mild compression fracture at the T12 level, probably unchanged
since CT of June 5, 2017.
5. New diffuse gastric uptake, possibly inflammatory. Attention on
follow-up imaging to ensure resolution."

She got into MSK urgent care center with an episode of atrial fibrillation on July 11, 2017. They also did a CT scan of the brain without contrast, that came back clear. While in the hospital they started noticing a rapid drop in her platelets levels to 35. They evaluated and decided this was due to an autoimmune reaction to the immunotherapy, and put her on daily 60 mg of Prednisone. The platelets were rising slowly to 48 at her discharge a week later. During 6 days at home after that she was feeling really weak and kept vomiting, and on July 24th, she fainted while getting up (her husband caught her) and we went back to the MSK urgent care. There they saw the platelets dropped back to 35, and started suspecting the bone marrow involvement. We refused the bone marrow biopsy, since after discussing with Dr Wolchok, our best bet is to try more immunotherapy (Ippi/Nivo) and they are planning to do it on Wednesday next week. It looks like mom is not eligible for any other clinical trials, since her platelets are around 24 now, and the minimum requirement for the trials is 100 (sometimes 75).
She had blood transfusion done before getting discharged from the hospital this Friday, since her hemoglobin dropped to 7.
It looks like we are down to very few options, if she is going to keep progressing on ippi and nivo.
Anyone has any suggestions for potential other effective treatments, for a 63 year old, with bone-centric acral lentiginous melanoma? Please help.
Note also, that mom has been following Gerson diet for a year with about 5 fresh juices per day, all organic, no sugar, no meat. But she started losing faith in it recently, and introduced the chicken, fish, back after her hip replacement surgery, since she needed strength. Now she cant hold much down anyway, with the nausea and vomiting. Today she had diarrhea and fever (up to 100.1), and we notified the melanoma fellow on call….
Any treatment suggestions, given her history, including the alternative clinics that were effective for the people that you know personally, are really appreciated!!

Thank you very much!